int leftLineCount = leftComparator.getRangeCount();
do {
RangeDifference diff = differences[diffIndex];
if (diff.kind() == RangeDifference.CHANGE) {
int nextChangedLine = diff.leftStart();
// output contextLineCount number of lines (if available) or all lines if contextLineCount == -1
if (pos != 0) { // at start of file, skip immediately to first changes
int beginContextEndPos = pos + config.getLinesBeforeSkip();